Straightening mechanism



July 4, 1939.

G. E. NIGHTHART STRAIGHTENING MECHANISM Filed Jan. 21 1937 8 Sheets-Sheet 1 INVENTOR.

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ATTORNEY.

July 4, 1939 G. E. NIGHTHART STRAIGHTENING MECHANISM 8 Sheets-Sheet 2 TT/wyar/rmer ATTORNEY.

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STRAIGHTEN ING MECHANISM Filed Jan 21, 1937 fiewm ATTORNEY.-

July 4, 1939.

G. E. NIGHTHART STRAIGHTENING MECHANISM INVENTOR ATTORNEY.

Filed Jan. 21, 1957 -Y 4, 1939- G. E. NIGHTHART 2,164,343

STRAIGHTENING MECHANISM Filed Jan. 21, 1957 s Sheets-Sheet 5 VIIIII'II'I'I' ATTORNEY.

July 4, 1939. v G. E. NIGHTHART STRAIGHTENING MECHANISM Filed Jan. 21, 1937 8 Sheets-Sheet 6 INVENTOR. QT/Wgavwaer d6 M ATTORNEY.

July 4,, 1939. G. E. NIGHTHART STRAIGHTENING MECHANISM Filed Jan. 21, 193 8 Sheets-Sheet 7 INVE TOR. QE/Wykvvmzr c a um ATTQRNEY.

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e. E. NIGHTHART STRAIGHTENING MECHANISM 1957 8 Sheets-Sheet 8 Filed Jan. 21

Q INVENTOR.

UHHH IHH "UN llll IIII IIIIIL Patented July 4, 1939 PATENT OFFICE STEAIGHTENING MECHANISM George E. Nightbart, New Remington, 1%., assignor to Aluminum Company of America, Pittsburgh, Pa., a corporation of Pennsylvania Application January 21,

13 Claims.

This invention relates to the straightening of bars, shapes, and the like, which, after being given their cross-sectional configuration by rolling, extrusion, and like processes, are found to be bent, twisted, or warped along their longitudinal axes. More particularly, the invention relates to straightening such products by stretching the material beyond its elastic limit and simultaneously removing any tendency to skew.

It is an object of the invention to provide an improved method and apparatus for straightening bars, shapes, and the like. Generally stated, the primary object is to provide improvements in a stretching machine in which all types of irregularities may be removed, and requiring only one handling operation of the material. Another object is the provision of apparatus which is adapted togrip the material to be straightened, irrespective of the type of irregularity, without resorting to preliminary straightening operations.

Fig. 1 shows a plan view of a straightening machine constructed according to the invention, with portions of the main frame broken away;

Fig. 2 shows a side elevatlon of the machine 5 shown in plan in Fig. -1; r

Fig. 3' shows a sectional plan view of the hydraulic actuating mechanism of the straightening machine, with portions broken away; I

Fig. 4 shows a. side elevation of the mechanism shown in plan in Fig. 3;

Fig. 5 shows a side elevation, partly in section, of the headstock mechanism;

Fig. 6 shows a plan view, partly in section, of the headstock mechanism shown in elevation in Fig. 7 shows an end elevation, partly in section, of the headstock, looking at the grip'ping end;

Fig. 8 shows an end elevation, partly in section, of the headstock, looking at the drive end;

Fig. 9 shows a typical section through the gripping heads of both the tailstock and headstock;

Fig. 10 shows an end view of the gripping mechanisms of the head and tailstock, with a workpiece in gripping position;

Fig. 11 shows an 'end elevation, partly in section, of the tailstock mechanism viewed from the drive end. The break line is taken along XI-Xl of Fig. 12;

Fig. 12 shows a side elevation, partly in section, 50 of the tailstock mechanism;

Fig. 13 shows an end elevation, partly in section, of the intermediate clamping mechanism;

Fig. 14 shows a side elevation of the intermediate clamping mechanism.

55 Referring to Figs. 1 and 2, the inachine con- 1937, Serial No. 121,483 (Cl. 153-35) sists essentially of a heavy base frame I upon which are mounted for movement a headstock, generally indicated as 2, and a tailstock 3. The headstock is adapted for movement to effect the stretching operation by means of a hydraulic, 5

mechanism 4. The tailstock is adapted for movement along the base frame to accommodate dif- Ierent lengths of material. The base frame is provided with a plurality of holes 5, preferably equally spaced along its length, with which aplunger mounted in. the tallstock is adapted to cooperate to fix the position'of the tailstock with respect to the frame during the stretching operation. The spacing of the holes 5 is such that the distance between any two holes is less than the total movement of the headstock when actu-' ated by the hydraulic mechanism.

, For the elimination ofcertain types of eccentricities occurring in material to be straightened, it is sometimes desirable to provide clamping mechanism positioned intermediate the tail and head stocks. The reference numeral 6 indicates one form of such mechanism.

Hydraulic actuating mechanism Figs. 3 and 4 illustrate the hydraulic actuating mechanism. The cylinder I cooperates with the slidably mounted main plunger 8, which also cooperates with the stationary smaller diameter plunger 9. For travel in the direction opposite to that required for stretching, fluid is pumped through the opening ID in the plunger 9, pushing the plunger 8 in a forward direction. For the stretching operation, the fluid is let into the cylinder I through the openings l I, moving the main plunger 8 back over the plunger 9, the opening Ill in the plunger-9 during this operation serving as an outlet for the fluid contained in the chamber l2 in the plunger 8. This construction permits the use of a single fluid pressure source for effecting the stretching'operation and the return operation. Due to the difference in volumes required to move the plunger in the stretching direction as compared with that in the return direction, a rapid return travel is effected. 45

To support the plunger 8 in its run-out posi- 1 tion, a carriage i3 is provided, running on tracks mounted on the top of the cantilevered portion ll of the main frame I. It is apparent that when a stretching operation is being performed there is a tendency to deflect the main frame, as it is acting as a column with an eccentric load applied substantially ou the center line of the cylinder. Alignment of the plunger 8 is maintained by cantilevering the portion ll of the frame and 55 within the cylinder'for purposes to be described thus permitting this portion to assume the slope imparted to the cylinder 1 by the deflection of the frame when under load.

Suitable packing for the plunger 8 is provided at I5 and it. This packing should be of such nature that it will permit rotation of the plunger later.

H eadstock Figs. 5, 6, 7, 8, 9, and 10 illustrate in more detail the construction of the headstock 2. The headstock is adapted for movement along the base i, and is kept in alignment with the top fiange or plate ll of the base by suitable guides It. To facilitate movement along the base, rollers l9 are provided. The frame members 28 and M in which the rollers 98 are mounted are adapted to permit rotation of the chucking structureof the headstock. The rotation of this portion is within the bushings 22 and 23.

The rotatable portion of the headstock has mounted thereon a ring-gear 24 which is in engagement with a pinion 25 mounted in member 20. The pinion is driven by a worm gear 21 co-- I operating through a worm 28, with a suitable power source such as a motor 29. The rotatable portion of the headstock is in threaded engagement with and is keyed to the portion 30 of the main plunger of the hydraulic mechanism. Thus, the rotation of the headstock effected through the pinion 25 and the ring gear 24 is transmitted to the main plunger 8 within the hydraulic cylinder.

Mounted within the rotatable portion of the headstock are a plurality of gripping jaws 3| and 3m. The jaws 3| have a.linkage with a common yoke member 32. This member is adapted for movement by anair cylinder 33 in which is mounted a plunger 34. The jaws 3| are adapted for, sliding cooperation with the inclined surfaces 35 provided in the rotatable portion of the head, and are connected to the yoke 32 through links 35 which are provided with spiral grooves 31 adapted to cooperate with springs 38. In the forward movement of the jaw members 3| to effect a gripping action on a bar or shape to be stretched, the springs 38 act in compression by pressure transmitted from the air cylinder 33. The gripping action is augmented during the stretching operation by the tendency of this operation to pull the jaws further down on the inclined surfaces 35. When the jaws are to be returned to their open position, the air cylinder pulls back the yoke 32, and a pull is exerted on the jaws by the springs. In their normal position, the coils of the springs 38 are spaced apart, as shown. Thus, when movement into gripping position is imparted by the air cylinder 33, the resilience of the springs will permit a degree of movement to accommodate small irregularities and insure a tight engagement of both jaws before the stretching operation is begun.

The jaws 3la in the gripping mechanism are each provided with separately controlled air cylinders 39, and may be independently brought into gripping coaction with the shape to be stretched after the two jaws' connected with the yoke member 32 are brought into engagement. As these jaws are independently operable, it is unnecessary that the springs acting in thelinkage between the jaws and the air cylinder have their coils spaced apart.

Figs. 9 and 10 show the method of gripping a- .shape in the gripping jaws. For convenience of illustration. the jaws are shown in cooperative relationship with a standard structural channel section which, in the present illustration, is the shape to be straightened. Gripping blocks 14 5 are mounted in grooves provided in the gripping jaws 3i and 31a, and held in position by set screws or some other suitable means. The gripping blocks are so formed as to conform closely with the particular shape to be straightened and to prevent any distortion of the shape by the gripping action of the jaws,.the block shown being particularly adapted in shape for the channel work-piece. Blocks suitably shaped for gripping any shape of work piece may be readily designed within the scope of the ordinary mechanics skill. It is essential, however, to obtain a satisfactory straightening of the material, that the gripping action in no way tends to deform the cross-sectional configuration of the material.

Tailstoclc Figs. 11 and 12 illustrate in detail the tailstock mechanism 3, which is adapted for movement along the base i on rollers 40. Two of these rollers are adaptedto be driven by a motor 4| through a train of gears 42, one of which is mounted on the common shaft of the rollers. When the tailstock has been located in the de sired position along the frame I, it is locked in position by dropping the anchor pin 43 into one of the holes 5 in the frame. The anchor pin is actuated by the double-acting air cylinder 44 through the bar 45. The downward movement of the bar 45 is adapted to actuate a valve mechanism 48 which energizes air cylinders 41 mounted one on each side of the frame.

Mounted one on each side of the tailstock frame are two pins 48, each having an inner end 49 which is provided with an inclined surface 50 complementary with the under-side of the top flange ll of the base. I. A rectangular hole 5| is provided in the bar 48 disposed at an angle of less than with the axis of the bar. A plunger connected to the air cylinder 41 is provided with complementary angular surfaces 52 which cooperate with the surfaces of the hole 5| to wedge the bar 48 into or out of engagement .with the surfaces of the frame member H. The upward movement of the pistons in the air cylinders 41 serves to clamp the tailstock tightly to the machine frame. This clamping action serves to prevent any tilting movement of the tailstock during Intermediate clamp 60 The "intermediate clamping mechanism is shown in, Figs. 13 and 14. The reference numeral 53 indicates the clamping mechanism frame adapted for movement along the stretcher base frame i on the rollers 54 driven by a suitable motor 55 through the gear train 56. When properly positioned longitudinally of the bar or shape to be straightened, the clamping mechanism is fixed relative to the base frame by the grips 51 pivoted in the frame53 by pins 58. A shouldered screw 59 is mounted for rotation, which may be imparted by the handwheel 60, in a suitable journal 6| which is pivoted in the grip 51 by a pin 82. The threads of the screw 59 cooperate with the threads in the bar 63 oscillatably mounted in the frame .53 to clamp the base I and the clamping mechanism, for longitudinal travel.

The bar or shape to be straightened is gripped by suitably shaped jaws 65 mounted on screw 66, the threads of which cooperate with the internal threads in the sleeve 61. The external threads on the sleeve 6? cooperate 'with the threads in the fixed nut 58. The sleeve 61 is rotated by the gear 89 mounted thereon and cooperating with the gear I0 mounted on the keyed shaft ii. The shaft H is driven by suitable worm and gear mechanism I2 driven by the handwheel it. ,The upper and lower jaws are actuated in identical fashion by the common shaft 1 I. Thus, upon rotation of the handwheel 13, the gripping jaws are brought into clamping engagement with the shape.

Operation The mode-of operation .is dependent entirely upon the character and degree of irregularity axis, the straightening operation is effected by; placing the ends of the shape in the head and tail stock gripping means and the hydraulic mechanism is actuated to subject the shape to tension in excess of the elastic limit of thematerial.

When, however, the shape is twisted or skewed, the one end is placed in the tailstock gripping means and the headstock is rotated until the gripping means therein are properly positioned for gripping engagement with the opposite end of the shape. Suflicient tension is then applied by actuation of the hydraulic stretchingmechanism to virtually eliminate any axial bow, and the headstock gripping means are rotated in a direction opposite to the shape until the elastielimit of the material in torsional shear is exceeded to an extent suflicient to remove the twist permanently. The shape is then stretched beyond the tensile elastic limit to remove any axial bow. In some cases, it may be preferable to keep increasing the tension on the material at the sametime that the headstock is being rotated to induce the shearing stress necessary to remove the tendency of the shape to skew. When shapes are produced by some methods,

. and particularly the extrusion process, they will be virtually free from twist over a major portion of their length. and still be badly twisted over the remaining portion. If an attempt is made to straighten a shape having this type of irregularity by gripping the ends in the head and tailstock and rotating the headstock sufiiciently to remove the original twist, the previously straight portion may have a twist set up in the direction of rotation. To prevent setting up a twist in the straight portion, the intermediate clamp is positioned along the axis of the shape at the point where the initial twist begins, so that the rotation of the headstock is only imparted to that portion of the shape between the headstock and the intermediate clamp.

I claim:

1. In a machine for straightening bars and shapes, means for gripping the ends of material to be straightened comprising a pair of oppositely disposed jaws having common actuating means and a second pair of jaws actuated indemon actuating means twist existing in the having common actuating mea pendently of said first pair of jaws and ofeach other. and means adapted to actuate said gripping means to subject said material to tensile stress and torsional shearing stress.

2. In a machine for straightening bars and shapes, means for gripping the ends of material to be straightened comprising a pair of oppositely disposed jaws having common actuating means and yieldable means between said common actuating means and each jaw of said pair, and a second pair of jaws actuated independently of said first pair of jaws and of each other, and

'- means adapted to actuate said gripping means to subject said material sicnal shearing stress.

3. In a machine for straightening bars and shapes, a main frame, means for gripping the ends of the material to be straightened adapted for movement relative to each other along said frame, means to anchor one 'of said first mentioned means selectively at different spaced-apart points along the frame to accommodate varying to tensile stress andtoranchoring means adapted for cooperation with said frame'to prevent tilting of said anchored gripping ,means during the straightening operation.

4. In a machine for straightening bars and shapes, means for gripping the ends of material to be straightened, of oppositely disposed jaws having common actuatng means, yieldable means between said comand each jaw of said pair; and a second pair of jaws adapted to be actuated independently of said first pair of jaws and of each other, and means adapted to actuate said gripping means to subject said material to tensile stress.

5. In a machine for straightening bars and shapes, a main frame, means for gripping the ends of material to be straightened adapted for movement relative to each other along said frame to stretch said material, means for effecting relative rotation of said gripping means to subject said material to torsional shearing stresses, and

gripping means mounted on said frame inter-- said means comprising a pair lengths of material, and means actuated by said and adapted for movement relative to each other along said frame, hydraulic means comprising a plunger and cylinder for actuating the gripping means at one end of said material to subject said material to tensile stress, and means adapted to rotate said gripping means and said plunger to subject said material to torsional shearing stress.

7. In a machine for straightening bars and shapes, means for straightened, means for rotating said gripping means to twist the material about its longitudinal axis, and means adapted to actuate said gripping means to stretch the material comprising-a hydraulic cylinder and plunger, said plunger being so connected with said grippingmeansas to be rotated therewith.

8. In a machine for stretching bars and shapes,

a main frame, means mounted on said frame adapted for gripping the ends of the material to bestraightened comprising sets of jaws, each set consisting of a pair of oppositely disposed jaws yieldable gripping the material to be said first pair of jaws and of each other,

means between and each jaw of jaws adapted to said common actuating means said pair, and a second pair of be actuated independently of one of said gripping means being adapted for rotation and longitudinal movement relative to the other set of jaws to subject the material to torsional shearing and tensile stresses.

9. In a machine for stretching bars and shapes,

a main frame, means mounted on said frame adapted for gripping the ends of the material to be straightened comprising sets of jaws, each set consisting of a pair of oppositely disposed jaws having common actuating means, yieldable means between said common actuating means and each jaw of said pair, and a second pair of jaws adapted to be actuated independently of said first pair of jaws and of each other, one of said gripping means being adapted for rotation and longitudinal movement relative to the other set of jaws to subject the material to torsional shearing and tensile stresses, and the other of said gripping means being adapted to be anchored selectively at different spaced apart points along the frame to accommodate varying lengths of material, and means adapted for cooperation with said frame to prevent tilting of said anchored gripping means during the straightening operation.

10. In a machine for stretching bars and shapes, a main frame, a headstock and tailstock frame, means in both saidpoints along the'frame to accommodate varying lengths of material, and means adapted for cooperation with said frame to prevent tilting of said tailstock when anchored, means adapted to move saidheadstock relative to said tailstock to stretch the material, and means for rotating the gripping means in said headstock to subject the material to torsional shearing stresses.

11. In a machine for straightening bars and shapes, means for gripping the ends of the material to be straightened, said means comprising a pair of oppositely disposed jaws having common actuating means, yieldable means between said common actuating means and each jaw of said pair, and a second pair of jaws adapted to be actuated independently of said first pair of jaws and of each other, and means adapted to effect relative rotation of said gripping means to subject said materialto torsional shearing stress.

12. In a machine for straightening bars and shapes, a main frame, means forgripping the ends of the material to be straightened adapted for rotation relative material to torsional shearing stress, means to anchor one of said first-mentioned means selectively at different spaced apart points along the frame to accommodate varying lengthsof material, and means actuated by said anchoring means adapted for cooperation with said frame to prevent tilting of said anchored gripping means during the straightening operation.

13. In a machine for straightening bars and shapes, a main frame, means for gripping the ends of the material to be straightened adapted for movement relative to each other along said frame and adapted for rotation relative to each other, means to anchor one of said first-mentioned means selectively at different spaced apart points along the frame to accommodate varying lengths of materal, and means actuated by said anchoring means adapted for cooperation with said frame ,to prevent tilting of said anchored gripping means during the straightening operation.

GEORGE E. NIGHTI-IART.

to each other to subject said 

